Step 1: Understanding the menstrual cycle.
The menstrual cycle consists of several phases: the follicular phase, ovulatory phase, luteal phase, and menstrual phase. During the menstrual phase, the endometrial lining sheds, which leads to menstruation.
Step 2: Analyzing the options.
- (A) Follicular phase: This phase is marked by the development of follicles in the ovaries and the buildup of the endometrial lining, not shedding.
- (B) Ovulatory phase: This is when ovulation occurs, but the endometrial lining does not shed during this phase.
- (C) Menstrual phase: Correct. The menstrual phase is when the endometrial lining sheds, leading to menstruation.
- (D) Luteal phase: During this phase, the body prepares for pregnancy, and the endometrial lining thickens, but it does not shed.
Step 3: Conclusion.
The correct answer is (C), as the shedding of the endometrium occurs during the menstrual phase.
Final Answer: (C) Menstrual phase.